Sizing paper



Patented Nov." 3, 1936 SIZING PAPER Otto Kress and Charles E. Johnson, Appleton, Wls., assignors to The Institute of Paper Chemistry, Appleton, Wis., a corporation or Wisconsin No Drawing. Application March 2, 1935, Serial No. 9,015

" 11 Claims. (CI. 92-21) Our invention relates to the sizing of paper and has to do more especially with the manufacture of rosin-sized paper containing an alkaline earth filler.

55 scribe in our co-pending application Serial No.

3,807, filed January 28, 1935. This emulsion may, for example, consist of 10 parts of a protein material such as a soya bean or milk casein, which is dissolved with 0.7 part of soda ash in Heretofore, it has been considered inexpedient about 60 parts of water at about 65 C. To to produce, by standard paper-making processes, this warm solution are then added 5 parts of a a rosin-sized paper containing an alkaline earth suitable emulsifying agent, such as ammonium filler. While such papers have been produced, te, which ay a P o y been dissolved it has been only by employing inconvenient and in 5 parts of water. 'When solution of these inuneconomical processes, and the results have gredients a cu ed, 0 pa ts of pa a a 10' been far from satisfactory. The principal difing a melt point of approximately are ficulty lies in the fact that rosin sizing requires slowly run n in a o te ndit o th a t acid conditions, in view of the use of alum for t The agitation s Continued in y suitable precipitating the size, and alkaline earth filler apparatus until p ete e u lfi a ion has oo- 5 reacts-with the alum, producing an alkaline cond- The size s produced is ted to dition and thus preventing completion of the about 1 Cent Pa W War Water at sizing reaction. The only efforts to solve this approximately C- condition in the past have required deviation The filler y be lime recovered, a from standard paper-making operations d stated above, from the causticizing of burnt thus have not been satisfactory, as stated above. limestone or dolomite, although it Will be PDa 20 The use of alk l earth fillers is highly cut that our invention is applicableto various sirable in the manufacture of book, printing, other yp f filler whi m y be s p ibl to and writing papers for several reasons In t undesirable reaction with other elements of the first place, such fillers produce a high white furhish- The filler and the emulsion P p color; furthermore, an alkaline earth sludge is as described above are thoroughly mixed and usually available in most paper plant as a from 3 to 5 per cent of an acidic substance, such product from the production of caustic soda as alum, is run in gradually W e the itat o from burnt lime or dolomite, in connection with Continues, for the P o e of eak g t e t manufacture of soda, pulp emulsion. As a result, each particle of filler is After considerable experimentation, we have enveloped With a Sub-microscopic film of P -found that it is possible to use an alkaline earth fin, said mm of Paraffih being in turn coated filler in connection with rosin-sized pulp, em- With a film of Protein at ria We have demploying th usual t r plant practice, if the onstrated with special microscopic equipment filler is first sized or coated with a substance that such films actually are produced on the which is inert to the rosin-size reagents. We Particles 9 flner- 35 have found that by employing a colloidal sus The pre'sence of thfise coatings 1s pension of inert material, each particle of of f' lmpoftance the slzing and Paperalkanne earth fin may be provided with a making operations, inasmuch as the filler is protective film of such inert material which will tectefi from reaction with pulp'sizmg 40 be quite stable under all the conditions of standeredlents at the i tune the paramn 40 ard plant operation, preventing reaction of the 15 protected by the pmtem thus preventing filler with the alum or other ingredients of the a'ggIPmeIatiOH of the paramn to form large pulp sizing bath and producing no undesirable partlcles thereof which might produce wax spots effect at any point of the operation, and at the on the finished p same time yielding-the maximum benefit as a Pulp treatment 45 filler. We have found paraflin to be the most satisfactory size for the filler, but may use, in a 3 523 gggtgg s ff fi f i g gg lieu thereof, various other inert wax-like subp stances.

' There are mtroduced to the beater about 500 0 Sizmg the pounds of bleached soda pulp and about 500 According to our preferred embodiment, we pounds of sulphite pulp. After this material has introduce the inert material in the form of a been mechanically prepared in the usual mancolloidal emulsion of paraffin, such as we dener, there is added to this pulp in the beater about one per cent by weight of rosin as ordinary rosin stock'for the paper machine, showers, etc.- The resulting mixture onthe paper machine will be slightly alkaline with a pH range of about 7.2 to- 7.4.

The finished paper made from this stock will be fully sized, will offer no mechanical troubles on the papermachine, such as clogging of the wire, sticking, foaming, etc., and will be free from wax spots and all possible sizing defects.

Pulp mixtures of, stock containing alkaline earth fillers pre-sized in accordance with our invention described above are stable for long periods of time, even when subjected to constant agitation and high temperatures, and will show no tendency for the paraffin to separate.

Modifications of our invention will no doubt :uggest themselves to those skilled in the art vithout departing from the spirit of our inven- ;ion. Hence, we do not wish to be restricted to :he specific embodiments disclosed above or uses nentioned, but intend that the s e of our inention shall be determined from he appended :laims, which should be interpreted as broadly as be state of the art will permit.

We claim as our invention:-

1. The method of making sized paper com- Irising providing a pulp containing a set rosin ize, and particles of an alkaline earth filler maeriai, each of said particles being coated with a llm of waxy material, the latter being protected y a water-insoluble protein preventing agglomration of the waxy particles and producing paper herefrom.

2. The method of-making sized paper comprisag providing a pulp containing a rosin size, and articles of an alkaline earth filler material, each f said particles being coated with a film of parafn, the latter being protected by a water-insolble protein material preventing agglomeration i the paraflin particles, and producing paper nerefrom.

3. The method of making rosin sized paper omprising providing a pulp containing rosin size that has been set by an acidic material, and particles of an alkaline earth filler material, each of said particles being coated with a film of waxy material, the latter being protected by a waterinsoluble protein preventing agglomeration of the waxy particles, and producing paper therefrom.

l. The method of making rosin sized paper comprising providing a pulp containinga rosin size that has'been set by alum, and particles of an a} aline earth filler material, each of said partic es being coated with a film of wan material, the latter being protected by a waterinsoluble protein material preventing agglomeration of the waxy particles, and producing paper therefrom.

5. 'I'he method of making rosin sized paper comprising providing a pulp containing a set rosin size, and particles of an alkaline earth filler, each of said particles being coated with a film. of waxy material, the latter being protected by a water insoluble protein material preventing agglomeration of the waxy particles, said protein material being selected from the group consist- J ing of milk and soyabean casein, and producing paper therefrom.

6. The method of making rosin sized paper comprising providing a pulp containing a set rosin size, and particles of an alkaline earth filler material, each of said particles being coated with a film of paraffin, the latter being protected by a water-insoluble protein material preventing agglomerationof the paraffin particles, said pro tein material being selected from the group consisting of milk and soya bean casein, and producing paper therefrom.

7. As a new article of manufacture a sized paper substantially free from wax spots produced by theprocess of claim 1.

8. Asanew article of manufacture a sized paper substantially free from wax spots produced by the'process of claim 2.

9. As a new article of manufacture a sized paper substantially free from wax spots produced by the process of claim 3.

10. As a new article of manufacture a sized,

paper substantially free from wax spots produced by the process of claim 4.

11. As a new article of manufacture a sized paper substantially free from wax spots produced by the process of claim 5.

o'rro KRESS. CHARLES E. JOHNSON. 

